I haven't, but I know someone who has. It was prescribed for insommnia, but it didn't make him sleep, just groggy. When he did manage to fall asleep, it kept him out for 10 hours or more, and when he woke up he felt like he had the biggest hangover for the rest of the day. Doesn't sound like much fun to me.
http://www.rxlist.com/cgi/pharmclips...d=%20Valium%AE
RxList.com is a great site for looking up any kind of medication a doctor wants to put in you, fyi.